something is off brother, you said you are not a big eater, but how many cals do you eat a day? total protein a day? nobody is trying to insult you here, but 5ft 10 inch 165lbs something is not working and first thought goes to diet, I am only 2 inchs taller and i weighed 170lbs 15 years ago when i was in the army eating like shit and running 15-18 miles a week...
Post up your day to day diet, only trying to help..